1. Field of the Invention
The present invention relates to an interleaved flyback converter capable of decreasing switching loss.
2. Description of the Related Art
Generally, since a flyback converter may be simply configured, as compared to other converters, it has been mainly used as a small-capacity DC-DC converter requiring electrical insulation.
However, a flyback converter may have high switching loss and low efficiency due to leakage inductance of an isolation transformer. Therefore, there are limitations in using a flyback converter as a medium-capacity DC-DC converter.
In the case in which the isolation transformer is designed to have low leakage inductance in order to improve efficiency of the flyback converter, reverse-recovery current an output rectifying diode on a secondary side of the isolation transformer increases. In this case, switching loss on a primary side of the isolation transformer and an electromagnetic interference (EMI) noise level may be increased.
In order to solve the problems inherent in the above-mentioned flyback converter, an interleaved flyback converter has been introduced.
An interleaved flyback converter has a structure in which two or more isolated flyback converters according to the related art are connected to one another in parallel. The interleaved flyback converter operates so that respective flyback converters connected to one another in parallel uniformly share total output power. Therefore, the interleaved flyback converter may decrease ripple of input current and ripple of output voltage at the same time.
However, the interleaved flyback converter having improved characteristics as compared to the flyback converter according to related art also has a problem in that when output capacity of the DC-DC converter increases, the switching loss of a switch on the primary side of the isolation transformer increases significantly.
Patent Document 1 described in the following related art document relates to the interleaved flyback converter, but fails to disclose a configuration for improving switching efficiency at the time of power conversion.